In the nearby Whirlpool galaxy and its companion galaxy, M51b, two supermassive black holes heat up and devour surrounding material. These two monsters should be the most luminous X-ray sources in sight, but a new study using ...

Measurements of gravitational waves from approximately 50 binary neutron stars over the next decade will definitively resolve an intense debate about how quickly our universe is expanding, according to findings from an international ...

The opportunity to measure the gravitational waves of two merging neutron stars could offer answers to some of the fundamental questions about the structure of matter. At the extremely high temperatures and densities in the ...

Data recorded by NASA's Chandra X-ray Observatory of a neutron star as it passed through a dense patch of stellar wind emanating from its massive companion star provide valuable insight about the structure and composition ...

During the formation of a black hole, a bright burst of very energetic light in the form of gamma rays is produced, these events are called gamma ray bursts. The physics behind this phenomenon includes many of the least understood ...

A brief and unusual flash spotted in the night sky on June 16, 2018, puzzled astronomers and astrophysicists across the globe. The event—called AT2018cow and nicknamed "the Cow" after the coincidental final letters in its ...

ESA's high-energy space telescopes Integral and XMM-Newton have helped to find a source of powerful X-rays at the centre of an unprecedentedly bright and rapidly evolving stellar explosion that suddenly appeared in the sky ...

An unusual supernova studied by multiple telescopes, including the SOAR telescope and other telescopes at the National Science Foundation's (NSF) Cerro Tololo Inter-American Observatory (CTIO) and NSF's Kitt Peak National ...

Neutron star

A neutron star is a type of remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and roughly the same mass as protons. Neutron stars are very hot and are supported against further collapse because of the Pauli exclusion principle. This principle states that no two neutrons (or any other fermionic particle) can occupy the same quantum state simultaneously.

A typical neutron star has a mass between 1.35 and about 2.1 solar masses, with a corresponding radius of about 12 km if the Akmal-Pandharipande-Ravenhall (APR) Equation of state (EOS) is used. In contrast, the Sun's radius is about 60,000 times that. Neutron stars have overall densities predicted by the APR EOS of 3.7 to 5.9 × 1017 kg/m³ (2.6 to 4.1 × 1014 times Solar density), which compares with the approximate density of an atomic nucleus of 3 × 1017 kg/m³. The neutron star's density varies from below 1 × 109 kg/m³ in the crust increasing with depth to above 6 or 8 × 1017 kg/m³ deeper inside.. This is approximately the weight of the entire human population condensed into the size of a sugar cube.

In general, compact stars of less than 1.44 solar masses, the Chandrasekhar limit, are white dwarfs; above 2 to 3 solar masses (the Tolman-Oppenheimer-Volkoff limit), a quark star might be created, however this is uncertain. Gravitational collapse will always occur on any star over 5 solar masses, inevitably producing a black hole.